package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import jodd.util.StringUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.StringUtils;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.CACHE_NULL_TTL;
import static com.hmdp.utils.RedisConstants.CACHE_SHOP_KEY;
import static com.hmdp.utils.RedisConstants.CACHE_SHOP_TTL;
import static com.hmdp.utils.RedisConstants.LOCK_SHOP_KEY;
import static com.hmdp.utils.RedisConstants.SHOP_GEO_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {


    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private CacheClient cacheClient;
//    //线程池
//    private static final ExecutorService CACHE_REBUILD_EXECUTOR=Executors.newFixedThreadPool(10);
    @Override
    public Result querryById(Long id) {
        //缓存穿透
        Shop shop=cacheClient.queryWithPassThrough(CACHE_SHOP_KEY,id,Shop.class,id2->getById(id2),CACHE_SHOP_TTL,TimeUnit.MINUTES);
        //用互斥锁解决缓存击穿
        //Shop shop = queryWithMutex(id);
        //用逻辑过期来解决缓存击穿
        //Shop shop=queryWithLogicalExpire(id);
        //Shop shop=cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY,id,Shop.class,id2->getById(id2),CACHE_SHOP_TTL,TimeUnit.MINUTES);
        if(shop==null){
            return Result.fail("店铺不存在！");
        }
        return Result.ok(shop);
    }
/*    public Shop queryWithLogicalExpire(Long id){
        //1.从redis中查询商户缓存
        String  shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY+id);
        //2.判断是否存在
        if(StrUtil.isBlank(shopJson)){
            //3.不存在，直接返回
            return null;
        }
        // 4.命中,命中需要吧json反序列化为对象
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        JSONObject data = (JSONObject) redisData.getData();
        Shop shop = JSONUtil.toBean(data, Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();
        //5.判断是否过期
        if(expireTime.isAfter(LocalDateTime.now())){
            //5.1未过期直接返回店铺信息
            return shop;
        }
        //5.2过期，需要缓存重建
        //6.缓存重建
        //6.1 获取互斥锁
        String lockKey=LOCK_SHOP_KEY+id;
        boolean isLock = tryLock(lockKey);
        //6.2 判断是否获取互斥锁成功
        if(isLock){
            //6.3 成功,开启独立线程实现缓存重建
            CACHE_REBUILD_EXECUTOR.submit(()->{
                try {
                    //重建缓存
                    saveShop2Redis(id,CACHE_SHOP_TTL);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }finally {
                    //释放锁
                    unlock(lockKey);
                }
            });
        }
        //6.4 失败,返回商铺信息
        return shop;
    }*/
/*    public Shop queryWithMutex(Long id){
        //1.从redis中查询商户缓存
        String  shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY+id);
        //2.判断是否存在
        if(StrUtil.isNotBlank(shopJson)){
            //3.存在，直接返回
            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
            return shop;
        }
        // 命中是否是空值
        if(shopJson!=null){
            //返回一个错误信息
            return null;
        }
        //4. 实现缓存重建
        //4.1 获取互斥锁
        Shop shop = null;
        try {
            boolean isLock = tryLock(LOCK_SHOP_KEY);
            //4.2 判断获取是否成功
            if(!isLock) {
                //4.3 失败，则休眠并重试
                Thread.sleep(50);
                return queryWithMutex(id);
            }
            //4.4 成功，根据id查询数据库
            shop = getById(id);
            //模拟重建延时
            Thread.sleep(200);
            //5.不存在，返回错误
            if(shop==null){
                // 将空值写入Redis
                stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
                return null;
            }
            //6.存在，将数据写入redis中
            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }finally {
            //7. 释放互斥锁
            unlock(LOCK_SHOP_KEY);
        }
        //8.返回
        return shop;
    }*/
/*    public Shop queryWithPassThrough(Long id){
        //1.从redis中查询商户缓存
        String  shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY+id);
        //2.判断是否存在
        if(StrUtil.isNotBlank(shopJson)){
            //3.存在，直接返回
            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
            return shop;
        }
        // 命中是否是空值
        if(shopJson!=null){
            //返回一个错误信息
            return null;
        }
        //4.不存在，根据id查询数据库
        Shop shop = getById(id);
        //5.不存在，返回错误
        if(shop==null){
            // 将空值写入Redis
            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
            return null;
        }
        //6.存在，将数据写入redis中
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        //7.返回
        return shop;
    }*/
/*    private boolean tryLock(String key){
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key,"1" ,10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }
    private void unlock(String key){
        stringRedisTemplate.delete(key);
    }*/
    public void saveShop2Redis(Long id,Long expireSeconds){
        //1.查询店铺数据
        Shop shop = getById(id);
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        //2.写入redis
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(redisData));
    }
    @Override
    @Transactional
    public Result update(Shop shop) {
        if(shop.getId()==null){
            return Result.fail("店铺id不能为空！");
        }
        //1.更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY+shop.getId());
        return Result.ok();
    }

    @Override
    public Result queryshopByType(Integer typeId, Integer current, Double x, Double y) {
        //1.判断是否需要根据坐标查询
        if(x==null || y==null){
            //不需要坐标查询
            // 根据类型分页查询
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }
        //2.计算分页参数
        int from=(current-1)*SystemConstants.DEFAULT_PAGE_SIZE;
        int end=current*SystemConstants.DEFAULT_PAGE_SIZE;
        //3.查询redis，按照距离排行、分页 结果：shopId 、距离
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo() //  geosearch key bylonlat x y byredius 5 withdistance
                .search(SHOP_GEO_KEY + typeId, GeoReference.fromCoordinate(x, y), new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end));
        //4.解析出id
        if(results==null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> content = results.getContent();
        if(content.size()<=from){
            //没有下一页了
            return Result.ok(Collections.emptyList());
        }
        //4.1 截取从from到end的部分
        List<Long> ids=new ArrayList<>(content.size());
        Map<String,Distance> distanceMap=new HashMap<>();
        content.stream().skip(from).forEach(result->{
            //获取id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            //获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
        //5.根据id查询店铺
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("order by field (id," + idStr + ")").list();
         for(Shop shop:shops){
             shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
         }
        return Result.ok(shops);
    }
}
